title: Impaired dipsogenic and renal response to repetitive intracerebroventricular angiotensin II (AngII) injections in rats.
abstract: The role of the central nervous system (CNS) in the control of blood pressure and hydrosaline homeostasis has been demonstrated by several studies. While circulating angiotensin II (AngII) tends to retain sodium by a direct renal action as well as through aldosterone release, stimulation of brain AngII receptors has been reported to induce natriuresis. Repetitive intracerebroventricular AngII injection was recently demonstrated to be capable of leading to desensitisation of the dipsogenic effect of AngII stimuli. The aim of the current study was to investigate a possible central desensitisation to AngII stimuli by observing the effects of a low-concentration solution of AngII on the dipsogenic and natriuretic mechanisms in conscious rats, compared with appropriate age-matched 0.15 M NaCl-injected subjects, as evaluated by lithium clearance. The present report confirmed earlier reports on the potent natriuretic and dipsogenic effects of central AngII receptor stimulation. Natriuresis is mediated by a decrease in sodium reabsorption in the proximal and post-proximal tubule segments of the nephron. The current findings lend further support to the idea that AngII, in the CNS, is instrumental in the regulation of body fluid homeostasis. The magnitude of the dipsogenic and renal response to AngII was significantly decreased by repetitive stimulus.
authors.affiliation: Disciplina de Medicina Interna, Laboratório de Metabolismo Hidro-Salino, Núcleo de Medicina e Cirurgia Experimental, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Sao Paolo, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Zapparoli
authors.forename: José Francisco
authors.initials: JF
authors.lastname: Figueiredo
authors.forename: Patricia Aline
authors.initials: PA
authors.lastname: Boer
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Rocha Gontijo
mesh_terms: D000804:Angiotensin II / Q000008:administration & dosage* / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D007668:Kidney / Q000187:drug effects* / Q000502:physiology*; D007677:Kidney Function Tests; D008094:Lithium / Q000378:metabolism; D008845:Microinjections; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism; D013894:Thirst / Q000187:drug effects*
chemical_list: D000804:Angiotensin II; D008094:Lithium; D012964:Sodium; D011188:Potassium